Effectiveness of ChAdOx1 nCoV-19 and BBIBP-CorV vaccines against COVID-19-associated hospitalisation and death in the Seychelles infected adult population.

Background: The Seychelles COVID-19 vaccination campaign was initiated using two different vaccines during the first wave of the pandemic in 2021. This observational study estimated vaccine effectiveness against severe outcomes (hospitalisation and/or death) from individuals infected with COVID-19 in the Seychelles adult population during Beta and Delta variant transmission.

Methods: This nationwide retrospective cohort study included all Seychellois residents aged ≥ 18 years who tested positive by RT-PCR or rapid antigen test for COVID-19 between January 25, 2021, and June 30, 2021.